<Resolved> Convert QHash <long long int, QList<long long int>> into a QVariant

TheIlliterate

Hello Guys:
Another Conversion pain question

I have QHash <long long int, QList<long long int> > object which I need to convert to a QVariant. But I am unable to do so. Kindly anyone can tell me what i need to be doing in this case.

I really dont want to a use QHash <QString , QList <QVariant> > instead of QHash <long long int, QList<long long int> >

Regards

The Illiterate

sierdzio

@
// Setting:

QVariant storage = QVariant::fromValue(yourHashObjectPointer);

// Getting:
QHash <long long, QList<long long> > result = storage.value<QHash <long long, QList<long long> > >();
@

TheIlliterate

Thanks Sierdzio, but that did not work for me. I was still getting compilation erros
So I tried Registering my QHash type.

@typedef QHash<long long int, QList<long long int>> HashMap;
} /namespace custom/
} /namespace my/
Q_DECLARE_METATYPE( my::custom::HashMap );@

but still gives me compilation errors:

@usr/include/qt4/QtCore/qmetatype.h: In function 'void* qMetaTypeConstructHelper(const T*) [with T = QHash<long long int, QList<long long int> >]':
usr/include/qt4/QtCore/qmetatype.h:196:25: instantiated from 'int qRegisterMetaType(const char*, T*) [with T = QHash<long long int, QList<long long int> >]'
../xxxxx/xxxxx/xxxxx.hpp:xx:1: instantiated from here
usr/include/qt4/QtCore/qmetatype.h:141:22: error: invalid use of incomplete type 'struct QHash<long long int, QList<long long int> >'
usr/include/qt4/QtCore/qdatastream.h:66:37: error: declaration of 'struct QHash<long long int, QList<long long int> >'
usr/include/qt4/QtCore/qmetatype.h:142:43: error: invalid use of incomplete type 'struct QHash<long long int, QList<long long int> >'
usr/include/qt4/QtCore/qdatastream.h:66:37: error: declaration of 'struct QHash<long long int, QList<long long int> >'
usr/include/qt4/QtCore/qmetatype.h: In function 'void qMetaTypeDeleteHelper(T*) [with T = QHash<long long int, QList<long long int> >]':
usr/include/qt4/QtCore/qmetatype.h:198:22: instantiated from 'int qRegisterMetaType(const char*, T*) [with T = QHash<long long int, QList<long long int> >]@

SGaist

Hi,

You might have forgotten to include QHash. Otherwise it the typedef/Q_DECLARE_METATYPE combo works well.

TheIlliterate

Thanks SGaist. You are right :) I wasted a lot of time assuming one of the many included header files must already contains include for QHash, but they did not :(

Thanks a lot :)

Regards
The Illiterate

sierdzio

Qt headers use forward declaration to speed up compilation time. It's good practice to include everything that you declare. Avoiding module includes is also a good idea (so, no <QtCore> but <QString>).

TheIlliterate

Thanks sierdzio for the valuable tip :)

Regards
The Illiterate

SGaist

You're welcome !
Don't forget to set the thread's title to solved :)

TheIlliterate

Done! Thanks:)